The best type of affection is reciprocally life-giving: each receives affection with joy and gives it without effort, and each finds the whole world more interesting in consequence of the existence of this reciprocal happiness. There is, however, another kind, by no means uncommon, in which one person sucks the vitality of the other, one receives what the other gives, but gives almost nothing in return. Some very vital people belong to this bloodsucking type. They extract the vitality from one victim after another, but while they prosper and grow interesting, those upon whom they live grow pale and dim and dull.
Affection is responsible for nine-tenths of whatever solid and durable happiness there is in our natural lives.